Process of selectively polymerizing diolefins in an unsaturated and aromatic gasoline distillate



Plum June 14,1949

PROCESS OF BELECTIVELY POLG DIOLEFINS IN AN UNSA'I'UBA'I'ED AND AROMATICGASOLINE DISTILLATE Minor c. x. Jonea, Mountainside, and mam-a 0.Brandon, Elizabeth, N. 1., ausignors to Standard Oil DevelopmentCompany, a corporation of Delaware No Drawing. Application May is, 1946,

Serialhlo. 670,835

2 Claims. (01. 196- 78)- This invention relates to a process of treatinghighly cracked gasoline distillates to obtain valuable high dienecontent polymers and stabilized motor fuel products.

Intensive cracking processes have been developed for producing largeamounts of low boiling mono-oleflns and dioleflns needed for manufactureof synthetic rubber-like polymers. Also, in these processes are produceddistillates boiling in the gasoline range, of about 100 F. to 450 E.containing considerable amounts of aromatic hydrocarbons mixed withunsaturated hydrocarbons that are very unstable. The complexity and highinstability of these distillates created a problem of selectivityremoving the unstable components and, in doing so, forming high dienenumber polymers that are particularly useful by virtue of theirconjugated unsaturation.

An object of this invention is to provide a method of treating thatresults in the production of high diene number polymers having thepropert of reacting with relatively large proportions of maleicanhydride, and similarly being a capable of combining with largeproportions of sulfurv or other substances that add particularly tocondugated double bonds.

The present invention is based primarily on the discovery that thepresence of low boiling mono-oleflns in a distillate interferes withselec tive polymerization of higher boiling diolefln components in thedistillate, especially if the amount of low boiling dioleflns isreduced, and the desired selectivity is obtained in a clay treatment ofthe distillate freed of low boiling olefins at temperatures in the range250F. to 350"1. for a controlled contact period.

In accordance with the present invention, the conditions of thetreatment with the catalytic adsorbent have to be carefully controlledto obtain the desired products. The average optimum temperature of theadsorbent during the treatment is in the range 250 F. to 350 F. Theoptimum space velocity of the gasoline distillate feed is within thelimits of 0.2.to 1 volume of the dis- .tillate oil per volume of theadsorbent per hour.

A further object is to provide a. method of cracldng'of petroleumcracking occurs when the stocks are heated to temperatures in the rangeof 1000 F. to 1600" F. 'At these high temperatures, the cracking isbeneficially-carried out in the presence of steam or a gas that preventsexcessive coke formation. Substantial quan'tities of unsaturated gaseoushydrocarbonasuch as ethylene, propylene, butylenes, and butadlene, areproduced; The gasoline distillates yielded contain large amounts ofunstable hydrocarbons that readily form gums on oxidation; Among theunstable distillate components, compounds to be expected are typifled'byC5 to Cl: acyclic andcyclic dioleflns, such as pentadienes,cyclopentadiene, hexadienes, cyclohexadiene. and the like.

Clay treating processes known to havelu'aen used successfully ongasoline distillates produced under mild conditions of cracking werefoundunsuitable for treating distillates produced under severe crackingconditions.

sumcient to maintain the oil in liquid phase.

Following the treatment, the stabilized distillate is separated frompolymer and recovered by fractional distillation. v

Isoprene (2-methyl-L3-butadiene) is one of the low boiling C5 dioleflnsformed in substantial quantities by intensive cracking, and is purposelyseparated from the gasoline distillates on'account of its usefulness'inthe manufacture of synthetic rubber-like polymers. On clay treating theremainder of the gasoline distillates from which isoprene was removed,it was found thatthepolymer yield was high, but the diene numjber of thepolymer was'rather low, thus indicat- .ing that a considerable amount ofthe remaining -Q a fdioleflns interpolymrized with mono-olefins.

e We then discovered'that if the distillates'are' first processed toseparate not only the isopren'e but also low: boiiing-niono-olefins,such" as C5 to Ccoleiins, in cuts boiling below F., and the remaindersof the distillates are clay treated under optimum conditions. the yieldof high diene number polymer is more closely correlated to the diolefincontents of the feeds to the clay treat:

ment, and the treated distillates show considerable improvement instability, all of which-indicate desired high selectivity intionof-thedioleflns. f v I Accordingly, it is now demonstrated tobeadvantageous to remove low boiling C5 to C6 olefins in removing a C5diol'efin from the unsaturated and aromatic distillates produced byintense cracking before the distillates are-subjected to thepolymerizadistillates, freed or the low boiling unsaturates, 5

.are contacted in liquid phase with the polymerizing catalyst. They maybe percolated through a bed of solid catalyst in granular or lump form,so that the distillate oil in filtering down through the bed washes awaypolymer from the catalyst.

Floridin, iallers earth, Attapulgus clay, acidtreated clays,heat-treated clays, or other active siliceous adsorbents, such aszeolites, may be used as the polymerizing catalyst.

For the purpose of illustration, a mode or operation will be describedwith reference to gasoline distillates from a typical high-temperaturesteam-cracking process.

TABIE I 'hrprcar. Gamma Gammon Dara Fresh feed to cracking furnace,lbs./hr 10,322 Total feed to cracking furnace, lbs./hr 41,517 Steam feedto cracking furnace, lbs/hr--- 8,025

The following tabulated data were obtained from treatments of thenaphtha distillates under comparative conditions with the followingalterations of the distillates treated:

A. C5 diolefln (isoprene) removed, C5 to oiefins remaining in thenaphtha.

B. Cs diolefin (isoprene) left in with Ca and Cs olefins.

0. C5 diolefln (isoprene) removed with C5 and Cs olefins. 7

TABLEII TABLE In Poems Paonacrs Conditions and feeds the same as inTable I! A B C v ma n g move w mmfim W to c. oienns Feed with o. to 0.Ole- Itemaining C; to 0| fins from in Feed Olelins Feed Polymart Yield,Vol. 8

per can 17 10 Via 'E' 2, Q 2 #23 1 it; viii mo F11 s1 s1 UIIII 78.5 51.364.8 teases/a it? .7 a m a." l l aleic Anhy do Val- '69 76 11a in g l102 1115- Diane 150. from Maloic nnmlggfiige 81119... 11, 11 12 17, 19-

I. B. P.', e 296 440V 290 5 484 487 436 10 507 497 465 30 568 509 544 7,626 608 606 Check Inspections.

cg. Bromine adsorbed by components that react with maleio ydride pergram of polymer sample.

The foregoing data, including check results, verify that removal of Ctto Ca olefins with the C5 diolefln made the aromatic-unsaturated naphthasusceptible to a more selective polymerization of diolefins remaining inthe naphtha on treatment under optimum conditions with the activeadsorbent catalyst.

Typical gasoline distlllates of intense cracking processes have anilinepoints of about 0 F. or lower. They generally contain 20 to 40 volumeper cent aromatics, 50 to volume per cent mono-oleflns, and 10 to 20volume per. cent diolefins. A substantial part of these mono-olefin anddiolefins are C5 and Ca unsaturated hydrocarbons, which boil attemperatures below 140 F.

The polymers of increased diene number obtained bythe controlledselective polymerization of dioleflns in the naphtha distillatesfollowing removal of low boiling oleflns with low boiling diolefins arecharacterized by their ability to re- Nsrnms Paonncrs Faou CLAY Iaaarnvcor Bron- TEMPERATURE Cascnma Nsrnrns Drsmna'rns Operating conditions ofclay treatment Temperature, F 300 Pressure, lbs/sq. in Feed rate,V./V./hr 0. 25 Clay Attapulgus Isop rene Isop rene Removed, c. Remainingm ggggg g Na m In to Ca Oleflns with C5 to C; p spections Remaining in01am 0; to Us Oleflns I Food Product Feed Product Food Product A andHeat (ABTM), 1? 436 300 465 a sec 300 24s, Aniline Point, F- g 0- 0 2 210 0 Peroxide No 9 0. 4 10 0. 6 15 [0. 3 V 2' as 2 404 a I P30851101added prior 50 (1181211182108;

act and combine with large quantities of sulfur supplied as elementarysulfur, sulfur halides, or other sulfurizing agents. The unsaturatedpolymers may be'fully or partly sulfurized before being compounded withnatural or synthetic rubbers. They may be co-vulcanized with therubbers, in which they serve as plasticizers or extenders. They havebeen found to be particularly useful as plasticizers or softeners ofrubberlike copolymers of diolefins, such as the 001101;!- mers ofstyrene with butadiene or isoprene.

After separation of diolefins from the low boiling out of C5 to C6olefins, e. g., by selective absorption of the diolefins with anammoniacal cupreous salt solution, these Cs to Ca oleflns areadvantageously added to the stabilized aromatic naphtha product of theselectivity polymerization treatment to obtain a high quality gasolinemotor fuel.

It is to be understood that various modifications are intended to comewithin the spirit and scope of this invention as defined in the appendedclaims. I

We claim:

1. The process of selectively polymerizing dioleflns in an unsaturatedand aromatic gasoline 25 distillate from a high-temperature crackingprocess, to obtain high diene number polymers and stabilized motor fuel,which comprises removing from the distillate an unsaturated hydrocarboncut boiling below 140 F., passing the remainder of the distillateboiling above 140 E. into contact with catalytically active clay at anaverage temperature in the range of 250 F. to 350 F., said remainder ofthe distillate being in liquid phase and being contacted with the clayat a space velocity of 0.2 to 1 volume per volume of clay per hour, andrecovering the thus claytreated distillate freed of unstable diolefinsand a polymer of high diene number.

2. The process as defined in claim 1, in which diolefins are removedfrom the unsaturated hydrocarbon cut boiling below 140 F., andmonoolefins of the out are added'to the clay-treated distillate freed ofdiolefins.

MINOR C. K. JONES. RICHARD C. BRANDON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name 7 Date 1,937,759 Herthel Dec. 5, 19332,067,030 Van Peski Jan. 5, 1937 2,162,717 Hancock June 20, 19392,422,627 Martin et a1; June 17, 1947

